The present application relates generally metal and ceramic composites. More particularly, the application relates to methods of fabricating metal matrix composites, ceramic matrix composites, functionalized textiles, and rapid prototyping.
Rapid prototyping techniques have been developed for the rapid fabrication of parts based on computer assisted design (CAD) programs. Generally, these processes utilize data about a designed component that has been input into a CAD program. A computer uses the data to control a rapid prototyping system to create a three dimensional model of the component. The model may be useful in and of itself, or it may be used to produce molds that may in turn be used to make copies of the component.
There are a number of available techniques for rapid prototyping. U.S. Pat. No. 4,575,330 discloses methods of forming three dimensional models using stereo-lithography. Three dimensional models are built, layer by layer, from liquid photosensitive polymers that cure into a solid form when exposed to ultraviolet light. Models may be built upon a substrate that is submerged in a reservoir of the polymer. Liquid epoxies and/or acrylates may be used. An ultraviolet light source, such as a UV laser, patterns a cross section of the model. The UV light cures the liquid polymer to form a single layer of the three dimensional model.
The substrate and solidified layer are then lowered in the reservoir such that the solidified layer is covered with liquid polymer. The UV light source then patterns the second layer on top of the first. All the layers of the model are similarly formed until the entire component has been made. The component may then be removed from the reservoir.
Other techniques include laminated object manufacturing. Layers of paper having a heat sensitive adhesive coating are used to form a model component. A first layer is provided and the component cross section is patterned by a laser to cut the first layer of the component. A second layer of paper is positioned over the first, and the layers are bonded by a heated roller. The second component cross section is then cut with the laser and the process is repeated. Eventually, a solid block is produced with the component contained therein. The excess material is removed to provide the model component. The excess material areas of each layer may be cut by the laser during fabrication to facilitate removal of the excess material.
Laser sintering may also be employed as a rapid prototyping technique. U.S. Pat. No. 4,863,538 discloses methods for manufacturing three dimensional models by sintering plastic, ceramic, polymer, or metal powder. As in the other techniques, a model is built on a substrate. The substrate is covered with a layer of powder material. The cross section of the model is then pattered with a laser to sinter the powder to provide a solidified layer. An additional layer of powder is then spread over the first layer and the second layer of the model is patterned with a laser. The process is repeated until the model has been fabricated. This process allows for the formation of metal models, however the surfaces are generally grainy in nature as a result of the sintering process.
These techniques, while able to provide three dimensional models are limited in the types of materials that may be employed. For example, near net shape models made of metal and metal composites are difficult to form. Also, while metal powders may be used, the temperatures and/or other conditions required for sintering may prevent the effective use of metals with low temperature materials. Existing methods of rapid prototyping are not conducive to the formation of composites of metals with low temperature fibers such as cellulose, diamond, carbon nanotubes, aramids, Kevlar, silica, Teflon, and the like. Accordingly, it would be desirable to provide a method for the fabrication of prototypes that can utilize other materials and combinations of materials.